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Erik Rasmussen Chats With Kent About Maintaining Open-Source Libraries

Erik Rasmussen chats with Kent about maintaining a popular open-source library and the key things that need to happen in order for a library to take off.

Erik built the Redux Form library to help manage form states in Redux. He decided to open-source Redux Form, and it exploded and became very, very popular.

People kept coming up to Erik with additional use cases, and the form library itself kept growing to the point where the bundle size got out of hand and saying yes to all the requests for features created a monster.

So Erik came up with his second form library "final-form." This time he created a plugin architecture to reduce the maintenance and make the library more capable of handling unconsidered use cases.

Erik talks about the key things that need to happen for a library to take off. First, it has to documented well, and the motivation has to get explained clearly. Second, someone who has a following needs to love it and share it with people. Third, you've got to be there on the ground, ready to make quick fixes as people give them to you.


  • Erik Rasmussen

    Erik Rasmussen


    Kent C. Dodds: Hello friends, this is your friend Kent C. Dodds, and I'm joined by my friend Erik Rasmussen. Say hi Erik.

    Erik Rasmussen: Hello Kent, it's good to be with you.

    Kent C. Dodds: It's good to be with you too. So Erik is a maintainer of open-source, and that's what we're going to be talking about today is the open-source maintenance and authoring open-source libraries, managing open-source communities, that kind of thing. But I want the audience to get to know Erik a little bit. So Erik, could you just introduce yourself and tell us about you before we get into our chat?

    Erik Rasmussen: Sure. I'm an American from North Carolina who has been living in Spain for the past 14 years because I married a Spanish woman, and my day job is working with Java applications. But on the side, I love playing around with JavaScript and increasingly TypeScript and the React Community. I've been involved with React since the day it was released by Facebook, building little side projects and things. And at one point, for some reason, I decided to open-source a form library that I found useful to manage form states in Redux, and it sort of exploded and became very, very popular.
    And over the course of that time, I have learned an awful lot about the different use cases that different corporations all over the world have with forms. Things that never would have occurred to me when I was solving my own little problem with forms. And so I don't know, I find it very rewarding to help people with their problems in the open-source community. I can't really explain it because there's no money in it for sure. But it's nice to give back, I guess, is the way to say it.

    Kent C. Dodds: Yeah, absolutely. I know what you mean. And people who are listening who haven't really experienced that, they can maybe get a little taste by remembering building a good abstraction in your work projects. That's other people start using this function that you made, and it's saving them time and just multiply that by thousands. Because building an abstraction that so many people can use and save them time and improve the maintenance of their app is really rewarding. It's super cool. So you wrote the Redux final form, right? You have two form libraries. One that's the Redux thing and then one that's just kind of standalone. Can you talk about those a little bit?

    Erik Rasmussen: Yes. Redux form is the big one. It's by far the most used form library in React still. And it was sort of my first attempt at managing form states at a higher level because the React docs only ever show you how to manage pretty much the form state of one input. And if you think about it, what's the company that makes React? How many inputs do they have in their form? Facebook really only has one form input in any particular form. Right?

    Kent C. Dodds: Yeah.

    Erik Rasmussen: It's your status update, or it's your reply to the comment thread. So they haven't published a lot of thought about how to manage a form with 25 inputs. And so it was clear that the form state had to live up higher above in the parent of the forms of the inputs. And at the time, Redux was just becoming popular as a way to manage states even higher than the application level. And so I wrote a reducer to manage form states, and it worked pretty well. But what happened, and we can get into this with open-source maintenance, is people kept coming to me with additional use cases and, "What if it did this?" And, "I need this many, I need to make it dynamic where I don't know all the inputs that I'm going to have when I first mount the form," or "I need an array of fields," and things like this.
    And so the form library itself kept growing and growing and growing to the point where the bundle size sort of got out of hand and saying yes to all the requests for features created this sort of monster. So that's the first one. And I having seen all of these use cases and problems with form UI that people needed solving, I took a step back and looked at how ... "Is there a better way?" And that's when I came up with my second form library called final-form or react-final-form is the React version of it, where rather than holding states in Redux or even in component states, final-form is a standalone form states container that it gives you a way to add fields, and it will manage the values of those fields, and it will do run validation and will manage the errors of validation, and the submit errors and things like that.
    All the stuff that you need with managing form state and it's in the self-contained zero dependency pure JavaScript library. And then, once I had that, I was able to build this little thin veneer over it for React to hook it into React with connecting onMount to register the form and put the form in the context and allow the field components to register themselves. And so my two form libraries are Redux form and react-final-form.

    Kent C. Dodds: And, which one has your heart right now?

    Erik Rasmussen: Oh for sure the newer one, react-final-form. I pretty actively recommend that people migrate. And in fact, just this week, I published a migration guide, and it turns out that because both were written by the same person, the API is really quite similar. It's so easy to migrate. So many people have told me that they migrated, and it was just trivial to do. And it's way better on your bundle size. It's like from 26K down to 8K so.

    Kent C. Dodds: Oh wow. Nice. Cool. So sounds like a really interesting learning process for you as getting into open-source and having a wildly popular library, I don't know if you know, but in the AngularJS days, I published and maintained the angular-formly library. It's probably still the most widely used forms library in angular JS as much whatever that means. But yeah, so I know the pains of forms and people's constant requests, and it's just so easy to say yes because you know, especially as you're the maintainer, how to accomplish what it is that they're trying to do. And maybe there's a workaround for it, but it's like really hacky, and so you're just like, "Oh, I'll just make that easier." And you start adding specific use cases or support for very specific use cases in the library, and it just grows and grows, grows.
    You have a lot of if statements in the library to handle all of these different options and things, and it can become a bit of a weight on your shoulders. Did you ever feel like you were burned out on these libraries and maintaining this and then responding to all of the people's requests? And often, it's not just like a, "Hey, I need this new feature." But it's like, "How do you use your library?" And, "I obviously didn't read the manual." So like it can get easy to get worn out. Did you ever feel that way?

    Erik Rasmussen: I had sometimes when, yes, there were a bunch of issues and a bunch of people who saying, "Plus one on the issue." Which was always helpful. But I don't know I think I managed the burnout fairly well. There've been times when I take a whole week, and I don't even look at the open-source stuff because otherwise, you're just ... If you get up every morning and look at all the issues and look at all the stack overflow questions, it can become as stressful as a job and a job that pays zero. So that's not healthy. And for sure, you get to a point where you can no longer look at every issue or stay up to date with your GitHub notifications, for goodness sake. If you have a library that's at all popular, your GitHub notifications are just worthless noise, but I do check on the issues.
    Really GitHub needs a better way to vote on issues like some of the bug tracking software out there like Jira and whatnot that have voting on issues. It would be helpful for library maintainers if there was a way to see that this particular issue, in the list, had so many upvotes or whatever, but alas, we can't do that. We just have to look through the issues and see where the most comments are or something. But no. There were times where I had to just step away and go for a walk and just do something else. But I feel like I've maintained a fairly sane level of open-source communication [inaudible 00:11:31]

    Kent C. Dodds: Yeah. I feel that pretty strongly as well with my open-source projects that I have. It can be a bit of a pain. Well, one thing that I've found that can be really useful is building a community around the project and finding people who can help maintain and triage issues and also finding a place where you can just move support requests off of GitHub. And so the community learns that, "Oh, GitHub is not the place to do support. That's where I file issues or request features. And so like that's where I have spectrum." And so if somebody does ask a question, typically I or one of the other maintainers will redirect them to spectrum. And that's been really helpful. Do you find, in your maintenance of your projects, that lots of the issues are actually just support requests?

    Erik Rasmussen: Yeah. And I think in my contributing document, I try and point people towards stack overflow first because, especially with Redux form, there's so many people that use it. And so many times I will get to a stack overflow question and it will already be answered. It'll already have the checkmark of there's someone that just correctly answered it. So the community comes with popularity, and it's great that some people want to help each other out when using your library. I haven't really jumped into spectrum all that much. It's I don't know. I've been sending people to stack overflow mostly, but then people will also answer each other's issues on GitHub. So I don't know which is better. There's still no solid solution on a good way, in my opinion. I haven't seen a great way to manage an open-source community around a library.

    Kent C. Dodds: So, what makes you do it then? I'm curious. If it's such a challenge, is it worth the effort, and why is it worth the effort for you?

    Erik Rasmussen: Well, it's very rewarding to have someone say, "Oh, thank you. My entire team was blocked on this. We couldn't fulfill our requirements for this project." In my experience, the library consumers, the other developers, are very grateful for a library. They understand that you're saving them a whole bunch of time by releasing this code. And they're very just grateful. And it's nice to ... I don't know; it just feels good to help other people. You can't really put it anymore more succinctly than that.

    Kent C. Dodds: Yeah. There's like intrinsic reward for being somebody who basically your code is running in way more apps than you could possibly build yourself.

    Erik Rasmussen: Oh, yeah. That's another kind of cool thing that will blow your mind is when you have a million monthly downloads, you know that so many projects out there are using your code and it's always kind of fun where sometimes I'll be using a website, and I'll be like, "Oh this forum works pretty nice." And I'll view the source, and it turns out, "Oh, it's using my library." So that's always fun. Just to spot your work in the world. But I've heard, especially when you go to a conference or something, people will come up to you and be like, "Oh yeah, this multinational bank that I work for has been using your library for a couple of years now." And that just kind of blows your mind that so many people out there are running code that you wrote, which again, it doesn't pay the bills, but it's neat to know that you've helped.

    Kent C. Dodds: Yeah. Well, then there's also the added benefit of having more experience, right? You're certainly a better React's developer having been exposed to so many different use cases, and recognizing, "Oh." Maybe at your job, you're exposed to different use cases, but then somebody else has a particular way that they're using forms, and they're trying to retrofit your library to fit their use case, and it just doesn't work. And so they open an issue and now you've been exposed to a totally different way of building forms or using forms on the web. And so if you hadn't open-sourced it, then you wouldn't have been exposed to that kind of thing. And now because you are, you're more capable.

    Erik Rasmussen: Yes. It certainly broadens your horizons or your understanding of what people might need React component to do. One of the reasons that we really love what we do is that we love the problem-solving part of, "Can we get this to do this and how can we figure out a way to accomplish this?" And that's just fun. I mean, sometimes someone will come with an issue and say, "Hey, how can I get my form to do this?" And I will, without even trying, I'll come up with a solution. And then it's hard because then it's like this person can't see the answer, but you with your experience have, and now you have to take the time to explain it to them or implement it or whatever. But it's, I don't know, the reason I love programming is problem-solving and the creative ways that we can make code the best it can be.

    Kent C. Dodds: Yeah. And it is kind of fun to take there. And this is something that I did a lot with angular-formly is our website was basically just a ton of examples. And all of those examples came from when I would answer somebody's question, I'd given this example and then I'd put it on the website and instead of sending them a link to the JS Bin, which is what we were using back then, I would put it on the website and then send them a link to the website. And so after a while, you had tons of examples, and it was kind of a fun challenge every single time. How do I demonstrate this feature in a way that balances the line between contrived and real-world so that people can see the forest through the trees or whatever, and understand what is the key element that I'm trying to demonstrate here, but also how does this apply in a real-world scenario? And it is challenging, but it's challenging in a good way.

    Erik Rasmussen: Yeah. And that was one of the ways that I built react-final-form. Was that I had a list in my head of all these different ways that people needed forms to be built. And so I built. There are dozens of examples in the react-final-form docs of doing exactly what you said. Of course, nowadays, we use [codes and box 00:00:19:51], but it's, "I need a wizard form." Okay. "How do you build a wizard form?" Or, "I need a way to have some fields disappear when another field is a certain value." Things like this where, because even though in my Javi job, I never really had some of these requirements, I knew that those requirements existed out there because I had maintained Redux form for so long.
    And so, I was able to go and build all of these examples, and I found bugs in my library, and I made sure that my library could support all of these examples. And that's such a great way to teach people how to use your library. I always say I like to refer to Nuxt.js. One of the things I love about their repo is you can go to the examples directory, and there's 50 examples of how to use different other libraries with all the CSS and JS libraries. There's an example of how to use other libraries in Nuxt. And that gives me the confidence that, whatever future libraries, I'm going to need, the people at Zeit are going to work out how to use that with their system. And it's just nice to see so many examples. And whenever your use case comes up, and there's a whole bunch of examples, you can often times find a pretty close match to what it is you're trying to do and pull that example in and learn how to do it. It's way easier than; I don't know, trying to read long pros in documentation, I think.

    Kent C. Dodds: Yeah, I agree. You talked about with Redux form that people kept on bringing their use cases, and it would just bloat the library, and there are some problems with that where it's like the bundle size but also the cognitive load on anybody who's trying to learn this library. There's just such a huge API. But then you kind of reimplemented all those use cases in final-form, but the bundle size is lower, and I'm assuming that the API surface layer area is probably lower as well. So can you talk a little bit about how do I take a use case that somebody has and ensure that I can support it without increasing the bundle size or the surface area of the library? Do you have any tips for that?

    Erik Rasmussen: Well, one of the design goals of final-form from the beginning, was to keep the bundle size minimal. And so the way I did that was I created this sort of plugin architecture where you could apply, you could install this other library that worked well with final-form that gave you, for example, the ability to handle arrays of fields, whereas your defaults install of final-form and react-final-form isn't going to handle arrays of fields, but there's this other thing you can install that will allow that. And I really liked that's architecture because it's like you're building your own form library with these lego bricks every time to fit whatever your use case is. And especially now with code splitting and things, you can use a smaller version of a final-form for your login page, but then when you have to actually go to edit your account, or whatever, you can have the extra code that makes that possible. So from the very beginning, I wanted to make it flexible so that additional functionality could be added on like that.

    Kent C. Dodds: Yeah. Plugin architecture is really kind of a challenge, but it obviously is a really great way to make a library extensible is by kind of inverting control a little bit and giving people the ability to extend the capabilities of the core library. It's kind of actually what Babel went through when they switched from everything built into Babel 5, where everything was a plugin. I can't even imagine going back from that and saying, "Okay. Every Babel plugin is now built into Babel." That would just be a total nightmare. So it eases the maintenance chore for you, and when somebody comes to you with the use case that you just had never thought of before, you can say, "Well, you can build a plugin, and you don't have to make any changes to the library." So it just reduces the maintenance and also makes the library more capable to handle use cases that were never really considered or are frankly not really popular or frequently used use cases.

    Erik Rasmussen: Right. Because with Redux form, for example, your user has to download all of the code to manage complex arrays of fields. Even if you just have two fields on the page and that just seems dumb. If you can, you should just have them download the core thing that they need to manage your minimal form states. And then, if you need the additional functionality, you can add extra code to your bundle.

    Kent C. Dodds: Yeah. And so cool. So if I'm thinking I've got a utility in mind that I want to open-source, what's the process of getting that code open-source? I want to increase the impact of this code, and I want other people to use this. How do I go about effectively open sourcing this code in a way that will make that positive impact that I want?

    Erik Rasmussen: Right. Well, I mean, you make it public on GitHub and you npm-publish with a good README. Your README should explain your motivation, why this is useful, and show a quick bit of code that makes it clear how this is used. And then sometimes people ask me, "Hey, I've opened source this thing that I think is really useful. How do I get people to use it?" And that's a hard question to answer because you just ... The other day someone asked me that on Twitter, and the best response I could come up with is, "I guess just do a Twitter search for people discussing the kind of problem that your library solves. And then maybe sort of bud in and as humbly as possible say, 'Oh, I had that problem, and I wrote this little thing. You can use it if you want'."
    It's kind of rude to any mention of a competitor and say, "Hey, why don't you use my thing that I wrote?" I'm sure you've seen plenty of that, and again, if people use your thing or they don't. You're not losing anything if someone switches from your library to someone else's library; if anything, you're losing the having to maintain another user. Right? But on the other hand, it's gratifying to have people use your stuff. So it's complicated. If it's really useful, people will use it. I don't have anything else.

    Kent C. Dodds: Yeah. Typically, it happens kind of organically. When you have really good documentation, really good examples, and you're solving a problem that people really are experiencing, then typically it's going to be used. Often, it does take having somebody who has some sort of following to use it, really like it, and share it with people. That can be really helpful. Eventually, if it is actually solving people's problems, then that will likely happen. Now that actually happened to the Webpack project, when Pete Hunt decided it was a good idea.

    Erik Rasmussen: I love that talk. That was a world-changing talk when he met ... maybe you should link to that. That's great. Yeah.

    Kent C. Dodds: Yeah. For your library to really take off, it often does need some sort of help in that direction. But I typically don't find libraries that are not well documented, get to take off like that. That's kind of a barricade.

    Erik Rasmussen: Sure. Yes. Segmentation is key. And like I said, explaining the motivation. At the very top of your README should be, "Why I built this and what problem it solves." I've seen so many libraries where I look around, and it's like, "What does this even do?" And you're right; if you can get someone like Kent C. Dodds to retweet you, then you'll be off to the races.

    Kent C. Dodds: Well, yeah, I just want to be careful because people keep asking me to retweet their Redux state management middleware, or their Redux killer or whatever. I'm not interested in that. I don't use that stuff. So you need to find somebody who is experiencing the problem that you're solving and who is just entrenched in this kind of problem. Yeah. Because if they're not, then yeah, maybe they can retweet it, but they can't really say anything about it. And especially people who have a big following, don't want to share something with everybody that follows them that they don't really know about, that they haven't vetted. And they often don't have time to vet the project anyway.
    So that's why having really great documentation is key because I do sometimes feel comfortable when I go through the documentation, and I've only got 60 seconds to do this, so I get a really clear picture of what it does, and it looks like a pretty smart idea, then I'm fine tweeting that and saying, "Hey, this looks like it could be a good idea." And then it's your job, as the maintainer of the library, to take those eyeballs that I've given you, and turning those into users of the project and hopefully contributors of the project as well. So yeah, if I'm-

    Erik Rasmussen: And as soon as you-

    Kent C. Dodds: Sorry, go ahead.

    Erik Rasmussen: As soon as you launch your thing, you need to be willing to put in time to look at issues and fix bugs and add features. Because if you do get some eyeballs, you're going to get people saying, "Hey, can it do this in this case?" And you're going to get requests where people find bugs and the more on top of that you can be, the better chance you're going to have to actually get your thing off the ground. If you open-source something and then don't look at it for a couple months and people come and complain, and nothing happens, you're going to lose those people. You've got to be there on the ground, ready to make those quick fixes as people give them to you.

    Kent C. Dodds: Yeah. Great. So Erik, as we're wrapping up here, I think that our call to action for people, for this episode, should be to release some open-source software and it doesn't have to be the solution to date pickers on the web or something like that might be a little ambitious for your first open-source project. It could be just a little utility function that you found to be really useful for yourself. If this is your first time, it's less about getting a lot of users and more about learning the process of open sourcing some software. Which I think will help you develop some empathy for open-source maintainers, help you understand what the process of releasing software is like, which I think everybody should really learn about.
    And I can give people one resource that I've made and then maybe Erik, if you have some resources and ideas then that can be helpful. But I have this free course on egghead called how to write an open-source JavaScript library where I show you the process of open sourcing a library on npm, and so you can watch that course, and that could help you get something open-sourced. Do you have any other tips or ideas of how to help people get their utility open-sourced?

    Erik Rasmussen: I've lost track of the number of times when I've Googled how to do something, and I come up with a Kent C. Dodd's video explaining exactly how to do the one thing that I'm trying to do. Really, you've been so helpful. No, your video is probably a great place to start. The other thing I wanted to add was, right now we're at a time with React hooks. You can release a really useful hook that composes of a couple of React things, and there's a lot of useful things that can be released as a hook these days, because hooks are so relatively young, there's still a bunch of cool stuff that we're going to discover of a common hook use case, if you can think of something clever that solves some particular problem with hooks, that's a good place to start.

    Kent C. Dodds: Yeah. Absolutely. It's still like a pretty young ecosystem there. So there's a lot of opportunity. Very cool. Erik, it's been a pleasure to chat with you. I hope that people learn to create some open-source software and what management of open-source is like; it is super rewarding. It's also super challenging, which is, I guess, maybe part of the reason why it's so rewarding. Kind of go hand in hand, but yeah, as we wrap up, Erik, what are the best ways for people to get in touch with you if they have any questions or anything?

    Erik Rasmussen: Well, I'm @erikras on Twitter. E-R-I-K-R-A-S. And my final-form library is and any of those places. And Twitter is the most direct route to get in contact with me, and I would love to hear feedback from everybody. So

    Kent C. Dodds: Great. Thank you so much. And with that, we'll say goodbye, and we'll see you all later. Bye.

    Erik Rasmussen: Bye.